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AI robotics, robot learning, embodied AI, and engineering experience of Linji (Joey) Wang

Basics

Name Linji (Joey) Wang
Label Robot Learning Researcher & Robotics Systems Engineer
Email joewwang@outlook.com
Url https://linjiw.github.io/
Summary Computer Science Ph.D. researcher connecting adaptive RL training with robot policy integration. My research examines student-aware curricula over tasks (GACL), auxiliary rewards (Reward Training Wheels), and domain randomization (LUCID preprint), supported by C++/ROS 2/ONNX inference work and C/Python systems engineering at AWS.

Skills

Robot Learning
Automatic Curriculum Learning
Deep Reinforcement Learning
Teacher–Student Learning
Reward Shaping
PPO
VAE Task Representations
Sim-to-Real
Domain Randomization
Latent Temporal Representations
Robotics Systems
PyTorch
Isaac Gym
Isaac Lab
MuJoCo
ROS 2
ONNX Runtime
Navigation
Quadruped Locomotion
Off-Road Mobility
Humanoid Policy Inference
Programming
Python
C
C++
Bash
Database Systems
PostgreSQL
Database Internals
Query Processing
Join Optimization
Performance Analysis
Software and Experimentation
AWS
Streamlit
Statistical Hypothesis Testing
Docker
Git / CI-CD

Experience

  • 2023.08 - Present

    Fairfax, VA

    Graduate Research Assistant — Robot Learning
    RobotiXX Lab, George Mason University
    Student-aware curricula over tasks, rewards, and simulation conditions; advised by Dr. Xuesu Xiao
    • Developed GACL with VAE task representations, learner-performance history, and grounded task sampling for PPO in 128 parallel Isaac Gym environments. Reported simulation success: 81.85% navigation and 79.21% quadruped locomotion versus CLUTR at 76.67% and 74.65% (first author, IROS 2025)
    • Co-developed Reward Training Wheels to adapt auxiliary-reward weights while retaining the primary objective. Reported off-road simulation success: 76.67% versus 34.44% with expert rewards; physical completion: 5/5 versus 2/5 trials (co-first author, IROS 2025)
    • LUCID (preprint, 2026): execution-informed domain-randomization curricula for humanoid motion tracking. The study reports 88.9% versus 76.8% full-randomization simulation completion against filtered-error PI; physical G1 trials with 40 ms added delay: 38/60 versus 23/60
    • Third author on Moving Through Clutter (2026), a VR data-collection and evaluation framework for scene-aware humanoid locomotion with 348 trajectories across 145 3D scenes
    • Developing a C++/ROS 2 policy-inference stack for Unitree G1 with paired ONNX residual/base policies, metadata-driven observation construction, temporal history, normalization, and Isaac Lab–MuJoCo parity diagnostics
    • Co-authored RL-based Adaptive Dynamics Planning (4th author, ICRA 2026) and Decremental Dynamics Planning (3rd author, IROS 2025); the DDP-based RobotiXX system placed 2nd in both the simulation qualifier and physical finals of the 2025 BARN Challenge
  • 2026.05 - 2026.08
    Software Development Engineer Intern — Amazon Aurora PostgreSQL
    Amazon Web Services (AWS)
    Aurora PostgreSQL query-execution performance and compatibility
    • Implemented and extended Adaptive Join in C for Aurora PostgreSQL, adding support for additional join types and expanding supported query coverage
    • Built join benchmarks and synthetic-data generators; used statistical comparisons to investigate regressions across engine changes
  • 2025.05 - 2025.08

    Bellevue, WA

    Software Development Engineer Intern — RDS Proxy
    Amazon Web Services (AWS)
    Statistical performance testing and visualization infrastructure
    • Built a Streamlit application that unified multi-region RDS Proxy performance comparisons and regression investigation
    • Implemented regression detection using Welch's t-test, power analysis, and Bonferroni correction; integrated CloudWatch metrics into reproducible performance dashboards
    • Developed adaptive test selection with Thompson sampling and Bayesian optimization to prioritize informative test configurations
  • 2022.01 - 2023.05

    Pittsburgh, PA

    Research Assistant — 3D Perception and AR
    Computational Engineering and Robotics Lab, Carnegie Mellon University
    Deep learning for 3D augmented-reality scene completion
    • Built an AR scene-inpainting pipeline using GAN image completion plus RANSAC and DBSCAN point-cloud segmentation
  • 2021.09 - 2021.12

    Pittsburgh, PA

    Research Assistant
    Biorobotics Lab, Carnegie Mellon University
    Computer vision for recycled-material classification
    • Built a CNN and OpenCV pipeline for real-time recycled-paper classification

Education

  • 2023.08 - Present

    Fairfax, VA

    Ph.D. in Computer Science
    George Mason University
    Research focus: curriculum learning and reinforcement learning for robotics
    • Advanced Machine Learning
    • Deep Learning
    • Reinforcement Learning
    • Computer Vision
  • 2021.09 - 2023.05

    Pittsburgh, PA

    M.S.
    Carnegie Mellon University
    Mechanical Engineering
    • GPA: 3.94/4.0
    • Machine Learning
    • Deep Learning
    • Computer Vision
    • Deep Reinforcement Learning and Control
  • 2016.09 - 2021.05

    Cincinnati, OH

    B.S.
    University of Cincinnati
    Mechanical Engineering
    • Magna cum laude

Publications

Projects

  • 2025.08 - Present
    Humanoid Policy Inference Prototype
    Ongoing C++/ROS 2 prototype for Unitree G1 motion-policy inference
    • Added paired ONNX residual/base inference, metadata-driven observation assembly, history buffering, normalization, and Isaac Lab–MuJoCo parity diagnostics
    • Documented validation gates explicitly; no physical-deployment claim is made
  • LUCID: execution-informed domain randomization
    Preprint, 2026. Latent-Understanding Curriculum for Informed Domain Randomization in Humanoid Motion Tracking.
    • A frozen temporal encoder summarizes command–execution discrepancy; a bounded PI scheduler with return-based backoff paces shared randomization intensity
    • Study evaluates held-out motion tracking, an unseen 60 ms delay, and physical G1 trials across four motions, three checkpoints, and five repetitions per condition and method

Awards

Teaching

Languages

English
Fluent
Chinese
Native

Interests

Embodied AI
Curriculum Learning
Reinforcement Learning
Humanoid Locomotion
Scene-Aware Whole-Body Control